Drinking cup lids adapted to fasten over the rim or lip of drinking cups are well known. Such lids prevent spillage and evaporation of the beverage within the cup, and help insulate the contents of the cup from the ambient temperature by closing the cup opening. In their most simple form, such cup lids comprise a generally fiat lid surface in the form disk having a peripheral sealing skirt for securing the lid to the rim of the cup.
As shown in U.S. Pat. No. 4,629,088 issued to Durgin, improved lids also include an openable tear strip or flap allowing limited access to the contents of the container while still coveting most of the open end of the container. Thus, a user is able to drink from the cup while the spillage-prevention and insulation qualities afforded by the lid are still largely maintained. These prior art lids are attached to the rim of the cup by simply pressing the edge of the cup downwardly onto the cup causing the peripheral sealing skirt to frictionally receive the rim of the cup. Many such lids also include a radially inwardly directed ridge which is designed to have controlled resilient expansion capability to allow the ridge to "snap-over" the cup rim to secure the lid to the cup. However, such lids suffer include a lid to prevent spilling the contents of the cup. Also, the handle extends outwardly from the cup creating an awkward projection which may be easily struck causing the contents of the cup to spill. Moreover, the handle does not permit the user to grasp both sides of the cup thereby preventing the user from firmly and steadily supporting the cup and its contents.
U.S. Pat. Nos. 4,376,493 and 4,465,205 both disclose container closures having an annular flange or wall which is rotatable downwardly to engage the rim of the container. The flange is designed to wrap around and forcibly engage the container rim thereby securely retaining the lid on the container. However, these closures are not used to sealingly engage a drinking cup and, therefore, do not experience the problems associated with inadequate lid to cup sealing and insufficient thermal protection for a user's fingers. Other similar container closures are disclosed in U.S. Pat. Nos. 3,589,551 and 3,688,942.
Consequently, there is a need for a lid for a drinking cup which can be securely attached to the cup to provide an effective seal between the lid and the cup rim while also protecting the user's hand from the thermal effects of the contents of the cup as the cup is held and manipulated.